Wow that isn't good eh? and seems I have to agree with Winuser in that the network card must be faulty and if it is the GPU then I think I mentioned before they usually soldered into the board unless the machine you have got has a removable one. That is a fair bit of work to do though.

Have you run any GPU tests on the machine yet? If not try this and it might be worth watching this first How to your GPU - YouTube - on another machine of course.